Glomerular basement membrane (GBM) products in urines may be an indication of normal replacement or repair mechanisms to the GBM resulting from wear and tear or damage due to the numerous agents which filter through the glomerulus. In streptococcal related glomerulonephritis or other immunological nephritities breakdown of GBM occurs at a greater than normal rate. This breakdown may be the result of either cellular enzyme release or complement activation due to immunologic reaction. The overall objective of this project has been to develop methods for quantitating GBM in urine and relating, if possible, the amount to pathogenesis of glomerulonephritis. A specific bank of known kidney fixing (both linear and nonlinear pattern) antisera versus GBM products and streptococcal cell membrane products are employed in the detection of the urinary antigens. Urines which show quantities of GBM products on radial diffusion assay are confirmed by the ability of the urine concentrates also to adsorb out fluorescent kidney fixing antibodies. This approach will allow for a semiquantitative evaluation of level of urinary GBM to the changes seen on light, fluorescent and electron microscopy. It is further proposed that this procedure will also allow for the prediction of the presence and amount of immunologic deposits in the GBM in kidney biopsies. Finally, followup quantitation of urinary GBM may be related to prognosis of the individual nephritity.